1. Technical Field
The present invention relates to wireless networks, and, more particularly, to wireless networks that include one or more Low-Cost Internet Base Stations (LCIBs).
2. Description of Related Art
a. Cellular Wireless Networks
Many people use mobile stations, such as cell phones and personal digital assistants (PDAs), to communicate with cellular wireless networks. Service providers that operate these wireless networks typically distribute mobile stations to their subscribers, perhaps by selling the mobile stations at retail outlets or over the Internet, or perhaps by offering mobile stations at no cost to people that subscribe to a particular service plan. Service providers then typically assign to each mobile station a telephone directory number—often known as a mobile identification number (MIN) or mobile directory number (MDN)—under which a mobile station may operate. Via a manual or over-the-air provisioning process, the service provider will cause the mobile station to store its MIN in its Number Assignment Module (NAM). Furthermore, a mobile station typically is provided at the time of manufacture with an electronic serial number (ESN), which identifies the mobile station as a unique physical device.
These mobile stations and networks typically communicate with each other over a radio frequency (RF) air interface according to a wireless protocol such as Code Division Multiple Access (CDMA), perhaps in conformance with one or more industry specifications such as IS-95 and IS-2000. Wireless networks that operate according to these specifications are often referred to as “1xRTT networks” (or “1x networks” for short), which stands for “Single Carrier Radio Transmission Technology.” Another protocol that may be used is known as Evolution Data Optimized (EV-DO), perhaps in conformance with one or more industry specifications such as IS-856, Release 0 and IS-856, Revision A. Other protocols may be used as well, such as Global System for Mobile Communications (GSM), Time Division Multiple Access (TDMA), WiMax, and/or any others.
These networks typically provide services such as voice, Short Message Service (SMS) messaging, and packet-data communication, among others, and typically include a plurality of base stations, each of which provide one or more coverage areas, such as cells and sectors. When a mobile station is positioned in one of these coverage areas, it can communicate over the air interface with the base station, and in turn over one or more circuit-switched and/or packet-switched signaling and/or transport networks to which the base station provides access.
The base stations for these networks are typically not associated with any subscriber or small group of subscribers in particular; rather, they are placed in publicly-accessible locations and are used by the service provider's customers generally. These base stations collectively blanket large geographic areas with coverage; as such, they are referred to generally and herein as “macro (or macro-network) base stations” and the network they collectively form—or to which they collectively belong—is referred to generally and herein as the “macro network.”
Mobile stations and macro base stations conduct communication sessions (e.g. voice calls and data sessions) over frequencies known as carriers, each of which may actually be a pair of frequencies, with the base station transmitting to the mobile station on one of the frequencies, and the mobile station transmitting to the base station on the other. This is known as frequency division duplex (FDD). The base-station-to-mobile-station link is known as the forward link, while the mobile-station-to-base-station link is known as the reverse link.
Furthermore, using a sector as an example of a coverage area, macro base stations may provide service in a given sector on one carrier, or on more than one. Each macro base station might have a capability of providing service on a first set of carriers during normal operation, and in addition, on a second set of “overflow” carriers held in reserve as necessary to handle increases in traffic.
Mobile stations are programmed to use a pre-determined algorithm to select one of the carriers set forth in a channel-list message (CLM) to use in future communications with a base station. In particular, each mobile station may apply a hash function, perhaps keyed to its MIN and/or ESN, to select one of the carriers. When a mobile is not engaged in an active communication session, the mobile station does what is known as idling on the selected carrier, which means that the mobile station is tuned to that carrier for receiving page messages, SMS messages, and other similar messages, and that the mobile station will also send access requests for call origination and other purposes to the base station on that carrier.
b. Low-Cost Internet Base Stations (LCIBs)
Many macro-network subscribers, including private consumers and small businesses, among others, in addition to having wireless service (which may include data service) for their mobile station (or mobile stations), also have high-speed (a.k.a. “broadband”) Internet access through another communication channel. This other channel may be cable-modem service, digital-subscriber-line (DSL) service, satellite-based Internet service, and/or some other option.
In an exemplary arrangement, a user may have a cable modem connected (a) via coaxial cable to a cable provider's network and (b) via Ethernet cable to a wireless (e.g. IEEE 802.11 Wi-Fi enabled) router. That router may include one or more Ethernet ports to which additional computers or other devices may also be connected, and may include wireless-access-point functionality, providing a WiFi packet-data interface to, for example, laptop computers, digital video recorders (DVRs), appliances, and/or any other computing devices or wireless network adapters.
To address gaps in macro-network coverage (e.g. in buildings) and for other reasons, macro-network service providers have recently begun offering consumers devices referred to herein as Low-Cost Internet Base Stations (LCIBs), which may also be referred to as femtocells, femto base stations, femto base transceiver stations (BTSs), picocells, pico base stations, pico BTSs, microcells, micro base stations, micro BTSs, and other names. Note that “low-cost” is not used herein as a limiting term; that is, devices of any cost may be categorized as LCIBs, though most LCIBs typically will be less expensive on average than most macro-network base stations.
A typical LCIB may be approximately the size of a desktop phone or WiFi access point, and is functionally a low-power, low-capacity version of a macro base station. Thus, a typical LCIB will use a normal power outlet, perhaps with a transformer providing a DC power supply. The LCIB may have a wired (e.g. Ethernet) or wireless (e.g. WiFi) connection with the user's router, and would thus have connectivity to the Internet and/or one or more other packet-data networks via the user's broadband connection. An LCIB may establish a virtual-private-network (VPN) connection over the Internet with an entity (e.g. a VPN terminator) on the wireless-service (macro-network) provider's core network, and thereby be able to securely communicate with the VPN terminator and other entities on that core network and beyond.
The LCIB also has a wireless-communication (e.g. CDMA) interface that is compatible with the user's mobile station(s), such that the LCIB may act as a micro base station, providing local wireless coverage on the wireless-service provider's network via the user's Internet connection. Usually, an LCIB will provide service on a single RF carrier (or on a single carrier per technology, where multiple technologies (such as CDMA and EV-DO) are supported), and also transmit what is known as a pilot beacon, which includes administrative messages and parameters that mobile stations can use to connect with the LCIB. LCIBs typically also include a Global Positioning System (GPS) receiver for receiving and decoding GPS signals for use in determination of location, as well as for use in synchronizing operations with other LCIBs and with the macro network based on timing information embedded in the GPS signal.